\begin{tikzpicture}
	\tkzDefPoints{0/0/C, -0.5/3/A,  2/0/B, 1.5/3/D}
	\tkzInterLL(C,D)(A,B)   \tkzGetPoint{O}
	\tkzDrawSegments(A,B  C,D)
	\tkzMarkAngle[size=0.4](A,O,C)  \tkzLabelAngle[pos=0.7](A,O,C){$1$}
	\tkzMarkAngle[size=0.6](D,O,A)  \tkzLabelAngle[pos=0.9](D,O,A){$2$}
	\tkzMarkAngle[size=0.4](B,O,D)  \tkzLabelAngle[pos=0.7](B,O,D){$3$}
	\tkzLabelPoints[left](A, C)
	\tkzLabelPoints[right](B, D)
\end{tikzpicture}

